%0 Article %A Ádám András %D 1972 %G English %B Acta cybernetica %@ 0324-721X %T On some enumeration questions concerning trees and tree-type networks to the memory of Dr Catherine Rényi and professor Alfréd Rényi %U http://acta.bibl.u-szeged.hu/12181/1/cybernetica_001_fasc_003_129-145.pdf